1. Bureau of Communicable Diseases, Wisconsin Division of Public Health, Madison, Wisconsin
2. Office of Public Health Preparedness and Response, Centers for Disease Control and Prevention, Atlanta, Georgia
3. Wisconsin State Laboratory of Hygiene, Madison, Wisconsin
4. Division of Healthcare Quality Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia
5. Division of Foodborne, Waterborne, and Environmental Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia
6. Special Bacteriology Reference Laboratory, Centers for Disease Control and Prevention, Madison, Wisconsin